1. Field of the Invention
The present invention relates to a push button switch and a switching device.
2. Description of the Background Art
FIG. 12 is a schematic cross section showing a first example of a conventional push button switch. Referring to FIG. 12, the push button switch mainly has resin keys 101 and a base rubber 103. The resin keys 101 are made of a resin and adhered to the base rubber 103. The base rubber 103 has base plate supported portions 103a and 103b which are thick portions and actuator portions 103c. The base plate supported portions 103a and 103b are portions for supporting the base rubber 103 on a base plate 105. The actuator portions 103c are portions in each of which a metal plate 104 is pressed to perform switching.
FIG. 13 is a schematic cross section showing a second example of a conventional push button switch. Referring to FIG. 13, the push button switch mainly has base bodies 201 of keys (buttons) and a film 202. The film 202 is formed on the surface of the base bodies 201 and has permeability (translucency) so that the underlayer permeates through the film 202. The base body 201 has an actuator portion 201a formed integrally with the base body 201. The actuator portion 201a is a portion in which a metal plate 204 on a base plate 205 is pressed to perform switching.
In the push button switch shown in FIG. 12, in the case of making a design on the surface of the resin key 101, printing or coating is performed. There is, however, a problem such that when an operation of depressing the resin key 101 is repeated for switching, the printing or coating is peeled off.
The push button switch shown in FIG. 13 has a problem such that water enters between the base body 201 and the base plate 205 from the outside of the device to thereby short-circuit the switching portion and penetrates to the inner side to short-circuit a motor or the like housed in the device.
It is also necessary to pay attention so that deterioration in the touch at the time of depressing a key for switching is not caused.
An object of the invention is, therefore, to provide a push button switch and a switching device capable of preventing a design in printing, coating, or the like from being peeled off and preventing intrusion by water.
Another object of the invention is to improve the touch in switching operation.
A push button switch of the present invention is a push button switch for performing a switching operation by pressing a metal plate on a base plate by depression of a button, having: base rubber, a base body of the button, and a film. The base rubber is disposed on the base plate and has an actuator portion capable of pressing the metal plate. The base body of the button is attached to the base rubber. The film is formed on the surface of the base body and has permeability.
In the push button switch of the invention, a permeable film is formed on the base body of the button. The film is made of a material having wear resistance higher than that of printing or coating. Consequently, the peeling due to wear of the film at the time of the switching operation can be prevented.
Since the film has permeability, the design on the underlayer can permeate the film and is displayed. By coloring the film, the degree of freedom in designing can be increased.
The base rubber is prepared by using a material different from the material of the base body of the button. By the base rubber, intrusion of water into a region between the base plate and the base rubber can be prevented. Thus, a short circuit in a switching portion and a short circuit in a motor can be prevented.
In the push button switch, preferably, the base rubber has thick base plate supported portion on the surface of the base plate. The film has a flange portion extending from a side portion of the base body to an outer periphery side so as to have a gap between the flange portion and the surface of the base rubber. The flange portion is disposed so as to avoid a region just above the base plate supported portion.
As described above, since there is a gap between the flange portion of the film and the surface of the base rubber, the operation load can be lessened without disturbing the depression deformation of the base rubber by the flange portion at the time of the button depressing operation. Specifically, when the flange portion of the film is adhered to the surface of the base rubber, the adhered portion disturbs the deformation in the base rubber at the time of the depressing operation, so that the operation load increases. There is no such increase in operation load.
Since the flange portion is disposed so as to avoid a region just above the base plate supported portions, the flange portion does not interfere with the upper ends of the base plate supported portions at the time of the button depression operation, so that the operation load can be lessened. That is, when the flange portion is disposed in the region just above the base plate supported portion, the flange portion interferes with the upper ends of the base plate supported portion at the time of the depressing operation and the operation load increases. There is no such increase in operation load.
Since the flange does not interfere with the upper ends of the base plate supported portion, the space between the flange portion and the base rubber can be reduced to be smaller than the operation stroke, and it becomes easy to reduce the thickness of the device body.
Preferably, in the push button switch, a space between the flange portion and the surface of the base rubber is smaller than a stroke of a switching operation of the metal plate.
As described above, the flange portion can be prevented from interfering with the base plate supported portion. The space between the flange portion and the surface of the base rubber can be made smaller than the stroke for the switching operation. Thus, the device body can be thinned.
The stroke of the switching operation of the metal plate in the application denotes a depression displacement amount until the switching is completed.
In the push button switch, preferably, the base plate supported portion have an outer peripheral portion disposed around the entire periphery of the base rubber, and the outer peripheral portion has a construction of preventing intrusion of water into a region surrounded by the base rubber and the surface of the base plate by being closely attached to the surface of the base plate.
The intrusion of water into a space surrounded by the base rubber and the base plate can be therefore prevented, so that a short circuit in the switching portion and a short circuit in the motor can be prevented.
A switching device according to one aspect of the invention has a base plate, base rubber, a plurality of base bodies of buttons, and a permeable film. On the base plate, a plurality of metal plates which are switched by being pressed are arranged. The base rubber covers the plurality of metal plates arranged, has thick base plate supported portions closely attached onto the base plate at the entire periphery, and has actuator portions in facing portions on the metal plates. The plurality of base bodies of buttons are attached to positions corresponding to the actuator portions on the base rubber. The permeable film is formed on the surface of the base body and has a flange portion extending from a side portion of the base body to the outer peripheral side.
A switching device according to another aspect of the invention has a base plate, base rubber, a plurality of base bodies of buttons, and a permeable film. On the base plate, a plurality of metal plates switched by being pressed by actuator portions are arranged. The base rubber covers the plurality of metal plates arranged and has thick base plate supported portions closely attached onto the base plate at the entire periphery. The plurality of base bodies of buttons are disposed on the base rubber and are pressed integrally with the actuator portions. The permeable film is formed on the surface of the base body and has a flange portion extending from a side portion of the base body to the outer peripheral side.
In the switching devices according to one and another aspects of the invention, a permeable film is formed on the base body of a button. The film is made of a material having wear resistance higher than that of printing or coating. Consequently, the peeling due to wear of the film at the time of the switching operation can be prevented.
Since the film has permeability, the design on the underlayer can permeate the film and is displayed. By coloring the film, the degree of freedom in designing can be increased.
The base rubber is prepared by using a material different from the material of the base body of the button. By the base rubber, intrusion of water into a region between the base plate and the base rubber can be prevented. Thus, a short circuit in a switching portion and a short circuit in a motor can be prevented.
In the switching devices according to one and another aspects, preferably, a gap is formed between the flange portion and the surface of the base rubber.
As there is a gap between the flange portion of the film and the surface of the base rubber, the operation load can be lessened without disturbing the depression deformation of the base rubber by the flange portion at the time of the switching. Specifically, when the flange portion of the film is adhered to the surface of the base rubber, the adhered portion disturbs the deformation in the base rubber at the time of the depressing operation. There is no such increase in operation load.
In the switching devices according to one and another aspects, preferably, a gap is formed between the flange portion and the base plate supported portion.
Since there is a gap between the flange portion and the base plate supported portions, interference of the flange portion with the upper ends of the base plate supported portions at the time of switching is suppressed, so that the operation load can be lessened. Specifically, when the flange portion is adhered to the base plate supported portion, the flange portion is pulled by the base plate supported portion at the time of switching and the operation load increases. There is no such increase in operation load.
Since there is a gap between the flange portion and the base plate supported portion, the space between the flange portion and the base rubber can be reduced so as to be smaller than the operation stroke, so that the thickness of the device body can be easily reduced.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.